From patchwork Fri Aug 12 15:27:46 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Catalin Marinas X-Patchwork-Id: 9277293 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id AA0F560752 for ; Fri, 12 Aug 2016 15:29:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9C97228A52 for ; Fri, 12 Aug 2016 15:29:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9101D28A57; Fri, 12 Aug 2016 15:29:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id AEB2C28A52 for ; Fri, 12 Aug 2016 15:28:59 +0000 (UTC) Received: (qmail 1924 invoked by uid 550); 12 Aug 2016 15:28:33 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: kernel-hardening@lists.openwall.com Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 32397 invoked from network); 12 Aug 2016 15:28:22 -0000 From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Cc: kernel-hardening@lists.openwall.com, Will Deacon , James Morse , Kees Cook Date: Fri, 12 Aug 2016 16:27:46 +0100 Message-Id: <1471015666-23125-8-git-send-email-catalin.marinas@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1471015666-23125-1-git-send-email-catalin.marinas@arm.com> References: <1471015666-23125-1-git-send-email-catalin.marinas@arm.com> Subject: [kernel-hardening] [PATCH 7/7] arm64: Enable CONFIG_ARM64_TTBR0_PAN X-Virus-Scanned: ClamAV using ClamSMTP This patch adds the Kconfig option to enable support for TTBR0 PAN. The option is default off because of a slight performance hit when enabled, caused by the additional TTBR0_EL1 switching during user access operations or exception entry/exit code. Cc: Will Deacon Cc: James Morse Cc: Kees Cook Signed-off-by: Catalin Marinas --- arch/arm64/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 69c8787bec7d..e7d5d0a7f6b4 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -784,6 +784,14 @@ config SETEND_EMULATION If unsure, say Y endif +config ARM64_TTBR0_PAN + bool "Priviledged Access Never using TTBR0_EL1 switching" + help + Enabling this option prevents the kernel from accessing + user-space memory directly by pointing TTBR0_EL1 to a reserved + zeroed area and reserved ASID. The user access routines + restore the valid TTBR0_EL1 temporarily. + menu "ARMv8.1 architectural features" config ARM64_HW_AFDBM